MCL1 and posterior cortical atrophy: ,26 This is further confounded by the fact that, unlike BCL2 which we have identified to be enriched in PCa tumors with evidence of lineage plasticity, MCL1 and BCL2L1 (the gene encoding BCLXL) are ubiquitously expressed in tumors from patients with lethal PCa (Figures 1A, 5A, and S1).11